Oral hygiene compositions include dental cleaning compositions such as toothpastes, tooth gels and tooth creams; gum-treating compositions and mouth washes. These compositions must meet a number of demanding requirements such as providing the desired hygienic activity and exhibiting storage stability. Importantly, to be attractive, these compositions must also be organoleptic, i.e., be pleasant to use, especially in terms of consistency, smell, taste and color.
Polyethylene glycols have found use in oral hygiene compositions. For example, U.S. Pat. No. 4,357,313 discloses tooth paste compositions containing about 5 to 20% by weight of polyethylene glycol having an average molecular weight of about 900 to 1600 to prevent or reduce drying (plugging) of the composition in a toothpaste tube. Also, lower molecular weight polyethylene glycols, e.g., having a molecular weight of less than about 800, have been proposed as humectants for preventing hardening of a toothpaste. For example, see U.S. Pat. No. 3,689,637. Polyethylene glycols of higher molecular weight have also been proposed as binders for toothpastes and gels. See, for instance, U.S. Pat. Nos. 2,501,145 and 3,228,844. In U.S. Pat. No. 3,689,637, high molecular weight polyethylene glycols, e.g., having a molecular weight of about 800 to 20,000, is disclosed as being capable of providing desirable texture to the dentifrice.
Polyethylene glycols can, however, impart an undesirable taste to the oral hygiene compositions. U.S. Pat. No. 3,703,578, for instance, discloses the use of water in tooth cleaning compositions to "counteract or reduce possible adverse tastes that may otherwise tend to be imparted to the tooth paste by particular polyoxyalkyleneglycols which are utilized in said tooth pastes." (column 4, lines 60-63). Typically, the lower molecular weight polyethylene glycols, i.e., having a molecular weight below about 800, which are normally liquids, impart a bitter taste and a pronounced bitter after taste. With higher molecular weight polyethylene glycols, i.e., having a molecular weight above about 1200, the taste is relatively bland with no pronounced after taste, but these polymers are solid at room temperature, thereby restricting their usefulness in oral hygiene compositions. A solid polyethylene glycol may not impart the desired consistency to a composition. Also, restrictions in formulation can occur if the sought composition is a liquid, gel or paste which may not exhibit proper flow characteristics or stability under temperature conditions to which it may be subjected. Moreover, the higher molecular weight polyethylene glycols have lower humectant properties.